Re: [Gegl-developer] Passing parameter to sampler from XML file
On 11-07-09 03:47, Nicolas Robidoux wrote: Let me try to explain the motivation for having different methods for transformations which are tuned for upsampling on the one hand, and downsampling on the other, and why a one size fits all stylishly scheme is neither easy to put together nor likely to be fast. Practical explanation: If one wants a cheap upsize, bilinear is acceptable, and bicubic/lanczos are better. However, when used to downsample, these schemes behave almost like nearest neighbour, which sucks for producing thumbnails, for which variants of box filtering are way better. On the other hand, box filtering behaves like nearest neighbour when upsampling. This suggests that getting a single scheme which is great in both situations is not so easy. One can actually implement a more refined box filtering which is less nearest neighbour-like when upsampling. An example of such a scheme is nohalobox (see bugzilla) = downsharp/smooth. It's a good all around scheme, and it's reasonably cheap, but when upsampling it can't compete quality and speed wise with, say, Lanczos or upsharp. Bit more math: Locally, one can characterize transformations pretty well by considering the singular values of its Jacobian matrix (think of them as the absolute values of eigenvalues of the affine transformation which is the best approximation to the transformation at the point under consideration). Suppose now that one wanted to construct a scheme which does well in all circumstances. When both singular values are larger than 1: Use a good upsampling scheme. When both singular values are smaller than 1: Use a good downsampling scheme. What about all the other cases? Although it is possible to blend schemes, if the warp has a lot of variability accomodating both schemes will introduce artifacts and, more importantly, is likely to lead to a scheme which is slow in all circumstances. Hence, in my opinion, the need for a choice. -- Now: A GUI with the purpose of image resizing could keep this issue invisible to users: If enlarging in both directions - upsharp or upsmooth (a smooth toggle could do) If shrinking in both direction - downsharp or downsmooth If enlarging in one and shrinking in the other: Either make an educated guess based on which one is most representative, or use the up scheme first, and then the down scheme. However, the point of the samplers is that if and when perspective and complex warping are implemented in gegl, they won't skip a beat. Nicolas Robidoux ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer I do get the point that choosing the right sampler for the task or situation is not that straightforward. However I think that the samplers should be callable using there technical name from the gegl lib. Making the names more gimp user friendly, or implementing a scheme is more for the end user tool. This way each tool that would use GEGL could implement he scheme most suitable for the tool. Geert ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
On 10-07-09 16:39, Nicolas Robidoux wrote: Most likely names of the resamplers at this point are either: upsharp and upsmooth or sharpupsize and smoothupsize for the samplers tuned for warps in which upsampling is more typical than downsampling (e.g., for image enlargement), and either downsharp and downsmooth or sharpdownsize and smoothdownsize for the samplers tuned for warps which mostly downsample (e.g., for producing thumbnails). - It turns out that the above schemes have cheap/less cheap versions. What I am thinking of doing is either prefixing or suffixing the above names with the word fast for the faster/lower quality versions, for example fastsharpupsize and fastsmoothupsize which would correspond to nohalo level 1 and snohalo level 1, while sharpupsize and smoothupsize would correspond to s/nohalo level 2. Feedback welcome. Nicolas Robidoux Laurentian University ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer I do not see any reason why one would have to specify up or downsize in the parameter since this can be determined from the in and output size, what about translations? If the difference between FastSharpUpsize and SharpUpsize is qualty then it should not be named Fast, FastSharp(Up|Down)size = SampleSharpGood = SharpGood Sharp(Up|Down)size = SampleSharpBetter = SharpBetter FastSmooth(Up|Down)size = SampleSmootGood = SmoothGood FastSmooth(Up|Down)size = SampleSmootBetter = SmoothBetter Or jus split it in 2 parameters, one for quality and one for effect. Geert ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
Suggestion implementing the s/nohalo family and the nohalobox family without an explicit, visible, parameter: Would it be possible/desirable to use the current code (which has a parameter) as some sort of template? Then, the nohalobox code would produce four independent samplers: sharperbox - smoothing = 0 sharpbox - smoothing = 1/3. smoothbox - smoothing = 2/3. smootherbox - smoothing = 1. which could be called like, say, linear. And the s/nohalo code would produce four independent samplers: sharper - nohalo (nohalo produces the same results as snohalo with smoothing = 0, just faster) sharp - snohalo with smoothing = 1/3. smooth - snohalo with smoothing - 2/3. smoother - snohalo with smoothing = 1. Nicolas Robidoux Universite Laurentienne ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
On Wed, Jul 8, 2009 at 8:43 AM, Nicolas Robidouxnrobid...@cs.laurentian.ca wrote: Suggestion implementing the s/nohalo family and the nohalobox family without an explicit, visible, parameter: Would it be possible/desirable to use the current code (which has a parameter) as some sort of template? Sure, for most uses both developers and users will desire a default sampler that just works and needs no tweaking. Additional properties to configure some of the samplers will make it harder both for users of GUIs as well as developers implementing or using operations that use the samplers. Fewer presets that cover normal use cases is probably better than many; this trimming down of the presets might be done in GUI layers code as well. The names for samplers would need some serious thought, linear, cubic and lanczos in current GIMP is already too techical for many users, most people would have no clue what box refers to in the suggested names. When exposes as for instance a drop down in the GUI these names need to be translatable into other languages as well. -- «The future is already here. It's just not very evenly distributed» -- William Gibson http://pippin.gimp.org/http://ffii.org/ ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
hi, Nicolas Robidoux schrieb: Can you (yes, I mean you) think of better names? uh, what, me? i wouldn't want to be bothered with choosing different samplers for up/down-scaling. So just let me choose from matching pairs of samplers. You know them better than i do... greetings, peter ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
yahvuu writes: uh, what, me? i wouldn't want to be bothered with choosing different samplers for up/down-scaling. (I'm surprised. You are always happy with the thumbnails you get? Result after rotating an image? Maybe I'm too invested in this field to know what matters and what matters not.) Peter just gave me more ideas of how it could look in a menu: bigger (sharp) and bigger (smooth) and smaller (sharp) and smaller (smooth) The fact that bigger can be used for arbitrary warps (including downsampling) and smaller can be used for arbitrary warps (including upsampling) should not confuse anyone. (I think.) Keep the ideas coming! Nicolas Robidoux Laurentian University ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
sharpEnlarge and smoothEnlarge and sharpShrink and smoothShrink (or sharpReduce and smoothReduce) ? PS Let me know if you'd rather I think about all this off list. ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
sharpsmall and smoothsmall and sharpbig and smoothbig ? In a scale image menu, the most likely appropriate method could be chosen automatically (depending on the requested resizing), with an extra smoothing toggle set by default to off. Nicolas Robidoux Universite Laurentienne ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
On Wed, Jul 8, 2009 at 1:08 PM, Nicolas Robidouxnrobid...@cs.laurentian.ca wrote: PS Let me know if you'd rather I think about all this off list. I dislike writing email, and you are almost using email like IRC, feel free to continue but do not expect much response from me in particular :d /pippin -- «The future is already here. It's just not very evenly distributed» -- William Gibson http://pippin.gimp.org/http://ffii.org/ ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
On Tue, Jul 7, 2009 at 10:25 AM, Nicolas Robidouxnrobid...@cs.laurentian.ca wrote: Adam Turcotte and Eric Daoust are implementing samplers (alternatives to nearest neighbour, bilinear, bicubic, lanczos... interpolation), names snohalo1 (tuned for upsampling) and nohalobox (tuned for downsampling), which both have a natural parameter. This parameter is basically the amount of extra antialiasing which is applied. The way the extra antialiasing is done is with a customized blurring operator in the case of snohalo1, and by enlarging the integration box (like for exact area box filtering) for nohalobox. Adam is nearly done (fingers crossed) implementing the paramter so that it is settable through xml commands. My question: We've settled on the name blur for this paramter, because for most people this is the visible effect, and I think most people understand that blurring can be useful to smooth out jaggies. Would you guys prefer another name for this visible parameter? Antialiasing, for example, seems like a good candidate, although it sounds a little too technical to my taste. I would feel more comfortable if this parameter was not exposed, but rather that sane presets were added and given names. In most cases the additional properties of for instance a displacement map operation might be visual and conceptual clutter getting in the users way. When it comes to naming it; I think perhaps smoothing is a good candidate. -- «The future is already here. It's just not very evenly distributed» -- William Gibson http://pippin.gimp.org/http://ffii.org/ ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
Nicolas Robidoux writes: For example, nohalo1 (same result as snohalo1 with smoothing = 0, but runs faster) would be sharper, snohalo1 with smoothing = 1 would be smoother, and snohalo1 with smoothing = .5 would be halfandhalf, or something kind of like that? If there were only four named presets, I supposed they could be sharpest, sharp, smooth, smoothest corresponding to smoothness = 0, 1/3, 2/3 and 1. with the added bonus that smoothness = 1/3 kind of corresponds to the Mitchell-Netravali choice of smoothing/interpolation balance. Øyvind: Does the above seem like a good choice, or did I change your mind with my smoothness slider idea (or do you like neither)? Nicolas Robidoux Laurentian University ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Re: [Gegl-developer] Passing parameter to sampler from XML file
On Tue, Jul 7, 2009 at 11:31 AM, Øyvind Kolåsislew...@gmail.com wrote: I would feel more comfortable if this parameter was not exposed, but rather that sane presets were added and given names. In most cases the additional properties of for instance a displacement map operation might be visual and conceptual clutter getting in the users way. When it comes to naming it; I think perhaps smoothing is a good candidate. I decided to tentatively implement this using a type field as with cubic. However, It appears to me that type is never actually set to anything other than cubic during initialization. How can I actually specify the type that I want to use? Adam Turcotte ___ Gegl-developer mailing list Gegl-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
